From patchwork Fri Jan 28 11:38:21 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Florian Westphal X-Patchwork-Id: 1585624 X-Patchwork-Delegate: pablo@netfilter.org Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org (client-ip=23.128.96.18; helo=vger.kernel.org; envelope-from=netfilter-devel-owner@vger.kernel.org; receiver=) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by bilbo.ozlabs.org (Postfix) with ESMTP id 4Jlb7m6qfLz9t25 for ; Fri, 28 Jan 2022 22:38:44 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237863AbiA1Lim (ORCPT ); Fri, 28 Jan 2022 06:38:42 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59050 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236998AbiA1Lim (ORCPT ); Fri, 28 Jan 2022 06:38:42 -0500 Received: from Chamillionaire.breakpoint.cc (Chamillionaire.breakpoint.cc [IPv6:2a0a:51c0:0:12e:520::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2ACC8C061714; Fri, 28 Jan 2022 03:38:42 -0800 (PST) Received: from fw by Chamillionaire.breakpoint.cc with local (Exim 4.92) (envelope-from ) id 1nDPaQ-0004un-Uh; Fri, 28 Jan 2022 12:38:38 +0100 From: Florian Westphal To: stable@vger.kernel.org Cc: , Pablo Neira Ayuso , Steffen Weinreich , Florian Westphal Subject: [PATCH 4.19.y] netfilter: nft_payload: do not update layer 4 checksum when mangling fragments Date: Fri, 28 Jan 2022 12:38:21 +0100 Message-Id: <20220128113821.7009-1-fw@strlen.de> X-Mailer: git-send-email 2.34.1 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netfilter-devel@vger.kernel.org From: Pablo Neira Ayuso commit 4e1860a3863707e8177329c006d10f9e37e097a8 upstream. IP fragments do not come with the transport header, hence skip bogus layer 4 checksum updates. Fixes: 1814096980bb ("netfilter: nft_payload: layer 4 checksum adjustment for pseudoheader fields") Reported-and-tested-by: Steffen Weinreich Signed-off-by: Pablo Neira Ayuso Signed-off-by: Florian Westphal --- This is already in the 5.y branches but 4.19 needs a minor tweak as ->fragoff member resides in xt sub-struct. net/netfilter/nft_payload.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/net/netfilter/nft_payload.c b/net/netfilter/nft_payload.c index b1a9f330a51f..fd87216bc0a9 100644 --- a/net/netfilter/nft_payload.c +++ b/net/netfilter/nft_payload.c @@ -194,6 +194,9 @@ static int nft_payload_l4csum_offset(const struct nft_pktinfo *pkt, struct sk_buff *skb, unsigned int *l4csum_offset) { + if (pkt->xt.fragoff) + return -1; + switch (pkt->tprot) { case IPPROTO_TCP: *l4csum_offset = offsetof(struct tcphdr, check);